The baryon density estimated in the
Ly at z 3 and in local
clusters of galaxies are both similar to the that from SBBN using low D/H.
This implies that there is little dark baryonic matter in the universe
[190].
This result seems conceptually secure, since there
is little opportunity to remove baryons from the IGM at z < 3 or
to hide them in dense objects without making stars which we would see
[191], and
the clusters are believed to be representative of the contents of the universe
as a whole today. However, the numerical estimates involved are not
yet accurate enough to rule out a
significant density (e.g. 0.5
b) of baryonic MACHOS.